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torvaldstorvalds
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Merge branch 'work.sysv' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull sysv updates from Al Viro: "Fabio's 'switch to kmap_local_page()' patchset (originally after the ext2 counterpart, with a lot of cleaning up done to it; as the matter of fact, ext2 side is in need of similar cleanups - calling conventions there are bloody awful). Plus the equivalents of minix stuff..." * 'work.sysv' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: sysv: fix handling of delete_entry and set_link failures fs/sysv: Replace kmap() with kmap_local_page() fs/sysv: Use dir_put_page() in sysv_rename() fs/sysv: Change the signature of dir_get_page() fs/sysv: Use the offset_in_page() helper sysv: don't flush page immediately for DIRSYNC directories
2 parents 397aa6b + abb7c74 commit d6b9cf4

3 files changed

Lines changed: 111 additions & 88 deletions

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‎fs/sysv/dir.c‎

Lines changed: 87 additions & 67 deletions
Original file line numberDiff line numberDiff line change
@@ -28,37 +28,50 @@ const struct file_operations sysv_dir_operations = {
2828
.fsync = generic_file_fsync,
2929
};
3030

31-
static inline void dir_put_page(struct page *page)
31+
inline void dir_put_page(struct page *page, void *page_addr)
3232
{
33-
kunmap(page);
33+
kunmap_local((void *)((unsigned long)page_addr & PAGE_MASK));
3434
put_page(page);
3535
}
3636

37-
static int dir_commit_chunk(struct page *page, loff_t pos, unsigned len)
37+
static void dir_commit_chunk(struct page *page, loff_t pos, unsigned len)
3838
{
3939
struct address_space *mapping = page->mapping;
4040
struct inode *dir = mapping->host;
41-
int err = 0;
4241

4342
block_write_end(NULL, mapping, pos, len, len, page, NULL);
4443
if (pos+len > dir->i_size) {
4544
i_size_write(dir, pos+len);
4645
mark_inode_dirty(dir);
4746
}
48-
if (IS_DIRSYNC(dir))
49-
err = write_one_page(page);
50-
else
51-
unlock_page(page);
47+
unlock_page(page);
48+
}
49+
50+
static int sysv_handle_dirsync(struct inode *dir)
51+
{
52+
int err;
53+
54+
err = filemap_write_and_wait(dir->i_mapping);
55+
if (!err)
56+
err = sync_inode_metadata(dir, 1);
5257
return err;
5358
}
5459

55-
static struct page * dir_get_page(struct inode *dir, unsigned long n)
60+
/*
61+
* Calls to dir_get_page()/dir_put_page() must be nested according to the
62+
* rules documented in mm/highmem.rst.
63+
*
64+
* NOTE: sysv_find_entry() and sysv_dotdot() act as calls to dir_get_page()
65+
* and must be treated accordingly for nesting purposes.
66+
*/
67+
static void *dir_get_page(struct inode *dir, unsigned long n, struct page **p)
5668
{
5769
struct address_space *mapping = dir->i_mapping;
5870
struct page *page = read_mapping_page(mapping, n, NULL);
59-
if (!IS_ERR(page))
60-
kmap(page);
61-
return page;
71+
if (IS_ERR(page))
72+
return ERR_CAST(page);
73+
*p = page;
74+
return kmap_local_page(page);
6275
}
6376

6477
static int sysv_readdir(struct file *file, struct dir_context *ctx)
@@ -80,11 +93,11 @@ static int sysv_readdir(struct file *file, struct dir_context *ctx)
8093
for ( ; n < npages; n++, offset = 0) {
8194
char *kaddr, *limit;
8295
struct sysv_dir_entry *de;
83-
struct page *page = dir_get_page(inode, n);
96+
struct page *page;
8497

85-
if (IS_ERR(page))
98+
kaddr = dir_get_page(inode, n, &page);
99+
if (IS_ERR(kaddr))
86100
continue;
87-
kaddr = (char *)page_address(page);
88101
de = (struct sysv_dir_entry *)(kaddr+offset);
89102
limit = kaddr + PAGE_SIZE - SYSV_DIRSIZE;
90103
for ( ;(char*)de <= limit; de++, ctx->pos += sizeof(*de)) {
@@ -96,11 +109,11 @@ static int sysv_readdir(struct file *file, struct dir_context *ctx)
96109
if (!dir_emit(ctx, name, strnlen(name,SYSV_NAMELEN),
97110
fs16_to_cpu(SYSV_SB(sb), de->inode),
98111
DT_UNKNOWN)) {
99-
dir_put_page(page);
112+
dir_put_page(page, kaddr);
100113
return 0;
101114
}
102115
}
103-
dir_put_page(page);
116+
dir_put_page(page, kaddr);
104117
}
105118
return 0;
106119
}
@@ -123,6 +136,11 @@ static inline int namecompare(int len, int maxlen,
123136
* returns the cache buffer in which the entry was found, and the entry
124137
* itself (as a parameter - res_dir). It does NOT read the inode of the
125138
* entry - you'll have to do that yourself if you want to.
139+
*
140+
* On Success dir_put_page() should be called on *res_page.
141+
*
142+
* sysv_find_entry() acts as a call to dir_get_page() and must be treated
143+
* accordingly for nesting purposes.
126144
*/
127145
struct sysv_dir_entry *sysv_find_entry(struct dentry *dentry, struct page **res_page)
128146
{
@@ -142,11 +160,10 @@ struct sysv_dir_entry *sysv_find_entry(struct dentry *dentry, struct page **res_
142160
n = start;
143161

144162
do {
145-
char *kaddr;
146-
page = dir_get_page(dir, n);
147-
if (!IS_ERR(page)) {
148-
kaddr = (char*)page_address(page);
149-
de = (struct sysv_dir_entry *) kaddr;
163+
char *kaddr = dir_get_page(dir, n, &page);
164+
165+
if (!IS_ERR(kaddr)) {
166+
de = (struct sysv_dir_entry *)kaddr;
150167
kaddr += PAGE_SIZE - SYSV_DIRSIZE;
151168
for ( ; (char *) de <= kaddr ; de++) {
152169
if (!de->inode)
@@ -155,7 +172,7 @@ struct sysv_dir_entry *sysv_find_entry(struct dentry *dentry, struct page **res_
155172
name, de->name))
156173
goto found;
157174
}
158-
dir_put_page(page);
175+
dir_put_page(page, kaddr);
159176
}
160177

161178
if (++n >= npages)
@@ -185,11 +202,9 @@ int sysv_add_link(struct dentry *dentry, struct inode *inode)
185202

186203
/* We take care of directory expansion in the same loop */
187204
for (n = 0; n <= npages; n++) {
188-
page = dir_get_page(dir, n);
189-
err = PTR_ERR(page);
190-
if (IS_ERR(page))
191-
goto out;
192-
kaddr = (char*)page_address(page);
205+
kaddr = dir_get_page(dir, n, &page);
206+
if (IS_ERR(kaddr))
207+
return PTR_ERR(kaddr);
193208
de = (struct sysv_dir_entry *)kaddr;
194209
kaddr += PAGE_SIZE - SYSV_DIRSIZE;
195210
while ((char *)de <= kaddr) {
@@ -200,27 +215,26 @@ int sysv_add_link(struct dentry *dentry, struct inode *inode)
200215
goto out_page;
201216
de++;
202217
}
203-
dir_put_page(page);
218+
dir_put_page(page, kaddr);
204219
}
205220
BUG();
206221
return -EINVAL;
207222

208223
got_it:
209-
pos = page_offset(page) +
210-
(char*)de - (char*)page_address(page);
224+
pos = page_offset(page) + offset_in_page(de);
211225
lock_page(page);
212226
err = sysv_prepare_chunk(page, pos, SYSV_DIRSIZE);
213227
if (err)
214228
goto out_unlock;
215229
memcpy (de->name, name, namelen);
216230
memset (de->name + namelen, 0, SYSV_DIRSIZE - namelen - 2);
217231
de->inode = cpu_to_fs16(SYSV_SB(inode->i_sb), inode->i_ino);
218-
err = dir_commit_chunk(page, pos, SYSV_DIRSIZE);
232+
dir_commit_chunk(page, pos, SYSV_DIRSIZE);
219233
dir->i_mtime = dir->i_ctime = current_time(dir);
220234
mark_inode_dirty(dir);
235+
err = sysv_handle_dirsync(dir);
221236
out_page:
222-
dir_put_page(page);
223-
out:
237+
dir_put_page(page, kaddr);
224238
return err;
225239
out_unlock:
226240
unlock_page(page);
@@ -230,19 +244,20 @@ int sysv_add_link(struct dentry *dentry, struct inode *inode)
230244
int sysv_delete_entry(struct sysv_dir_entry *de, struct page *page)
231245
{
232246
struct inode *inode = page->mapping->host;
233-
char *kaddr = (char*)page_address(page);
234-
loff_t pos = page_offset(page) + (char *)de - kaddr;
247+
loff_t pos = page_offset(page) + offset_in_page(de);
235248
int err;
236249

237250
lock_page(page);
238251
err = sysv_prepare_chunk(page, pos, SYSV_DIRSIZE);
239-
BUG_ON(err);
252+
if (err) {
253+
unlock_page(page);
254+
return err;
255+
}
240256
de->inode = 0;
241-
err = dir_commit_chunk(page, pos, SYSV_DIRSIZE);
242-
dir_put_page(page);
257+
dir_commit_chunk(page, pos, SYSV_DIRSIZE);
243258
inode->i_ctime = inode->i_mtime = current_time(inode);
244259
mark_inode_dirty(inode);
245-
return err;
260+
return sysv_handle_dirsync(inode);
246261
}
247262

248263
int sysv_make_empty(struct inode *inode, struct inode *dir)
@@ -259,9 +274,7 @@ int sysv_make_empty(struct inode *inode, struct inode *dir)
259274
unlock_page(page);
260275
goto fail;
261276
}
262-
kmap(page);
263-
264-
base = (char*)page_address(page);
277+
base = kmap_local_page(page);
265278
memset(base, 0, PAGE_SIZE);
266279

267280
de = (struct sysv_dir_entry *) base;
@@ -271,8 +284,9 @@ int sysv_make_empty(struct inode *inode, struct inode *dir)
271284
de->inode = cpu_to_fs16(SYSV_SB(inode->i_sb), dir->i_ino);
272285
strcpy(de->name,"..");
273286

274-
kunmap(page);
275-
err = dir_commit_chunk(page, 0, 2 * SYSV_DIRSIZE);
287+
kunmap_local(base);
288+
dir_commit_chunk(page, 0, 2 * SYSV_DIRSIZE);
289+
err = sysv_handle_dirsync(inode);
276290
fail:
277291
put_page(page);
278292
return err;
@@ -286,16 +300,15 @@ int sysv_empty_dir(struct inode * inode)
286300
struct super_block *sb = inode->i_sb;
287301
struct page *page = NULL;
288302
unsigned long i, npages = dir_pages(inode);
303+
char *kaddr;
289304

290305
for (i = 0; i < npages; i++) {
291-
char *kaddr;
292-
struct sysv_dir_entry * de;
293-
page = dir_get_page(inode, i);
306+
struct sysv_dir_entry *de;
294307

295-
if (IS_ERR(page))
308+
kaddr = dir_get_page(inode, i, &page);
309+
if (IS_ERR(kaddr))
296310
continue;
297311

298-
kaddr = (char *)page_address(page);
299312
de = (struct sysv_dir_entry *)kaddr;
300313
kaddr += PAGE_SIZE-SYSV_DIRSIZE;
301314

@@ -314,44 +327,51 @@ int sysv_empty_dir(struct inode * inode)
314327
if (de->name[1] != '.' || de->name[2])
315328
goto not_empty;
316329
}
317-
dir_put_page(page);
330+
dir_put_page(page, kaddr);
318331
}
319332
return 1;
320333

321334
not_empty:
322-
dir_put_page(page);
335+
dir_put_page(page, kaddr);
323336
return 0;
324337
}
325338

326339
/* Releases the page */
327-
void sysv_set_link(struct sysv_dir_entry *de, struct page *page,
340+
int sysv_set_link(struct sysv_dir_entry *de, struct page *page,
328341
struct inode *inode)
329342
{
330343
struct inode *dir = page->mapping->host;
331-
loff_t pos = page_offset(page) +
332-
(char *)de-(char*)page_address(page);
344+
loff_t pos = page_offset(page) + offset_in_page(de);
333345
int err;
334346

335347
lock_page(page);
336348
err = sysv_prepare_chunk(page, pos, SYSV_DIRSIZE);
337-
BUG_ON(err);
349+
if (err) {
350+
unlock_page(page);
351+
return err;
352+
}
338353
de->inode = cpu_to_fs16(SYSV_SB(inode->i_sb), inode->i_ino);
339-
err = dir_commit_chunk(page, pos, SYSV_DIRSIZE);
340-
dir_put_page(page);
354+
dir_commit_chunk(page, pos, SYSV_DIRSIZE);
341355
dir->i_mtime = dir->i_ctime = current_time(dir);
342356
mark_inode_dirty(dir);
357+
return sysv_handle_dirsync(inode);
343358
}
344359

345-
struct sysv_dir_entry * sysv_dotdot (struct inode *dir, struct page **p)
360+
/*
361+
* Calls to dir_get_page()/dir_put_page() must be nested according to the
362+
* rules documented in mm/highmem.rst.
363+
*
364+
* sysv_dotdot() acts as a call to dir_get_page() and must be treated
365+
* accordingly for nesting purposes.
366+
*/
367+
struct sysv_dir_entry *sysv_dotdot(struct inode *dir, struct page **p)
346368
{
347-
struct page *page = dir_get_page(dir, 0);
348-
struct sysv_dir_entry *de = NULL;
369+
struct sysv_dir_entry *de = dir_get_page(dir, 0, p);
349370

350-
if (!IS_ERR(page)) {
351-
de = (struct sysv_dir_entry*) page_address(page) + 1;
352-
*p = page;
353-
}
354-
return de;
371+
if (IS_ERR(de))
372+
return NULL;
373+
/* ".." is the second directory entry */
374+
return de + 1;
355375
}
356376

357377
ino_t sysv_inode_by_name(struct dentry *dentry)
@@ -362,7 +382,7 @@ ino_t sysv_inode_by_name(struct dentry *dentry)
362382

363383
if (de) {
364384
res = fs16_to_cpu(SYSV_SB(dentry->d_sb), de->inode);
365-
dir_put_page(page);
385+
dir_put_page(page, de);
366386
}
367387
return res;
368388
}

‎fs/sysv/namei.c‎

Lines changed: 22 additions & 20 deletions
Original file line numberDiff line numberDiff line change
@@ -153,19 +153,18 @@ static int sysv_unlink(struct inode * dir, struct dentry * dentry)
153153
struct inode * inode = d_inode(dentry);
154154
struct page * page;
155155
struct sysv_dir_entry * de;
156-
int err = -ENOENT;
156+
int err;
157157

158158
de = sysv_find_entry(dentry, &page);
159159
if (!de)
160-
goto out;
160+
return -ENOENT;
161161

162-
err = sysv_delete_entry (de, page);
163-
if (err)
164-
goto out;
165-
166-
inode->i_ctime = dir->i_ctime;
167-
inode_dec_link_count(inode);
168-
out:
162+
err = sysv_delete_entry(de, page);
163+
if (!err) {
164+
inode->i_ctime = dir->i_ctime;
165+
inode_dec_link_count(inode);
166+
}
167+
dir_put_page(page, de);
169168
return err;
170169
}
171170

@@ -227,7 +226,10 @@ static int sysv_rename(struct mnt_idmap *idmap, struct inode *old_dir,
227226
new_de = sysv_find_entry(new_dentry, &new_page);
228227
if (!new_de)
229228
goto out_dir;
230-
sysv_set_link(new_de, new_page, old_inode);
229+
err = sysv_set_link(new_de, new_page, old_inode);
230+
dir_put_page(new_page, new_de);
231+
if (err)
232+
goto out_dir;
231233
new_inode->i_ctime = current_time(new_inode);
232234
if (dir_de)
233235
drop_nlink(new_inode);
@@ -240,23 +242,23 @@ static int sysv_rename(struct mnt_idmap *idmap, struct inode *old_dir,
240242
inode_inc_link_count(new_dir);
241243
}
242244

243-
sysv_delete_entry(old_de, old_page);
245+
err = sysv_delete_entry(old_de, old_page);
246+
if (err)
247+
goto out_dir;
248+
244249
mark_inode_dirty(old_inode);
245250

246251
if (dir_de) {
247-
sysv_set_link(dir_de, dir_page, new_dir);
248-
inode_dec_link_count(old_dir);
252+
err = sysv_set_link(dir_de, dir_page, new_dir);
253+
if (!err)
254+
inode_dec_link_count(old_dir);
249255
}
250-
return 0;
251256

252257
out_dir:
253-
if (dir_de) {
254-
kunmap(dir_page);
255-
put_page(dir_page);
256-
}
258+
if (dir_de)
259+
dir_put_page(dir_page, dir_de);
257260
out_old:
258-
kunmap(old_page);
259-
put_page(old_page);
261+
dir_put_page(old_page, old_de);
260262
out:
261263
return err;
262264
}

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